She has gone from not making the final cut on “American Idol” Season to her first album winning her first Grammy – handed to her by a personal idol of her own, Whitney Houston.

And then of course there is her most visual transformation, going from a size 16 to size 6 as a Weight Watchers spokesperson – an 80-pound chiseling that will be on full display TONIGHT, when Hudson’s free streaming Live On Letterman concert from the Ed Sullivan Theater in New York starts at 9 p.m. ET . (Don’t forget you can see the entire performance HERE).